Rare diseases: the research network Europe had to build itself
Thirty million Europeans live with a rare disease. Only 6% of those conditions have an approved treatment. After decades of fragmented national efforts, a pan-European research alliance has just completed its first year — and the early results suggest the structural fix may finally be in place.
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At a Glance
Of the 6,000 to 8,000 known rare diseases, only 6% currently have an approved treatment. The core obstacle is not scientific: it is the size of patient populations, too small at the national level to run statistically valid clinical trials.
Launched in September 2024 under Horizon Europe — the EU’s €95.5 billion research and innovation program for 2021–2027 — ERDERA (European Rare Diseases Research Alliance) brings together more than 170 organizations across 37 countries with a total estimated budget of €380 million through 2031, of which approximately €150 million comes from the European Union.
In its first year, the alliance selected 18 transnational preclinical projects from 161 applications, engaged 29 national funders across 23 countries, and assembled 10,000 harmonized genomic and phenotypic datasets from previously unresolved cases — the first pan-European infrastructure of its kind.
The structural paradox of rare diseases
A disease is classified as rare in Europe when it affects fewer than one in 2,000 people. Taken individually, each condition affects a handful of patients. Taken together, the 6,000 to 8,000 documented rare diseases affect 30 million Europeans — roughly the combined population of Romania and Croatia.
This paradox — many patients in aggregate, too few for any single disease — is at the root of the therapeutic failure. Clinical trials require sufficiently large cohorts to reach statistical significance. With twenty, fifty, or a hundred patients per country, no EU member state can independently run a robust trial on an ultra-rare condition. The result: thousands of diseases remain outside the commercial radar of pharmaceutical companies, for lack of both economic viability and scientific critical mass.
That structural lock is what ERDERA is designed to break.
What one year of implementation has produced
The twelve-month assessment HaDEA (the European Health and Digital Executive Agency, the Commission body overseeing EU health research programs) made public in February 2026 documents operational results — not yet therapeutic ones. That distinction is essential and deliberate.
Seven integrated service areas are now fully operational: research coordination, a clinical trial network, a data infrastructure, training, patient engagement, regulatory alignment, and industry transfer. Deploying all seven simultaneously, across more than 170 organizations in 37 countries, within twelve months, is a governance result worth noting on its own terms.
The first Joint Transnational Call (JTC 2025) received 161 project proposals and selected 18, all targeting preclinical development. These projects focus on small molecules and biological therapies for conditions with no current treatment. They drew in 29 national and regional funders across 23 countries, with a combined funding package of €29 million. A second call (JTC 2026), focused specifically on unsolved genetic and non-genetic disease cases, is currently open.
Alongside this, the clinical network collected and harmonized 10,000 genomic and phenotypic datasets from previously unresolved cases — a cross-border resource that makes it possible, for the first time, to match clinical profiles that had remained invisible at the national level. The legal frameworks for secure, cross-border health data sharing are now in place.
Why European scale changes the math
Scientific coordination across member states existed before ERDERA, but in fragmented form. Two predecessor programs — E-Rare-3 (a European network supporting national rare disease research funding agencies) and the European Joint Programme on Rare Diseases (EJP RD) — had laid foundations since 2006. ERDERA consolidates and scales those efforts under a single architecture, coordinated by INSERM, France’s national institute for health and medical research.
A researcher working on an ultra-rare muscular dystrophy in Finland will never find enough patients in one country.
Connected to a clinical network spanning 37 countries, that same researcher can assemble a cohort of 200 to 300 patients — the threshold above which Phase II trials become statistically viable.
The EU’s contribution through Horizon Europe — €150 million out of €380 million total — is functioning as a financial lever: it unlocked the remaining €230 million from member states, associated countries, and private partners. Without the European program, that composite funding structure would not have been assemblable. The model has attracted attention beyond Europe: ERDERA is formally aligned with the International Rare Diseases Research Consortium (IRDiRC), the global coordination body that includes the U.S. National Institutes of Health and major funders from Japan, Canada, and Australia.
Who benefits — and what remains to be built
For the 30 million Europeans affected, the implications are direct. Most rare diseases have a genetic origin, manifest in childhood, and generate years of diagnostic delay. Studies suggest that the gap between first symptoms and accurate diagnosis can, in many cases, exceed five years. A harmonized, pan-European data infrastructure could significantly reduce that gap, as unresolved cases are matched against new genomic markers at continental scale.
Two limits need to be stated clearly. First, ERDERA has not yet produced a single approved treatment — the results to date are structural, and the path from preclinical trials to market authorization is measured in years, not months. Second, the model depends on regulatory interoperability between national health systems that remains, in several member states, a work in progress. The European Health Data Space — the EU’s framework for cross-border health data sharing, whose regulatory foundation was adopted in 2024 — is designed to address this, but its phased rollout leaves access gaps between countries in the near term.
The bottom line
The real question ERDERA now poses is not whether Europe can coordinate research — it just demonstrated that it can. The question is whether this critical-mass infrastructure will survive the political and budgetary cycles that have fragmented European rare disease efforts before. The alliance has secured funding through 2031. What the 18 current preclinical projects produce will determine whether the model attracts a second investment cycle — or remains a well-architected promise.
Sources: HaDEA · EURORDIS — Rare Diseases Europe · European Commission, Directorate-General for Research and Innovation · ERDERA (erdera.org)